The primary research goal is to define, molecular, and functional nature of antigenic peptides presented as HLA class I antigens and to evaluate their clinical significance. Studies are focused on peptides on renal allograft rejection, autoimmune renal diseases and breast and lung cancers. We are isolating HLA class I bound peptides from tumor cells using reverse phase HPLC, identifying biologically active fractions and analyzing them by capillary LC/MS and product ion spectra using database search algorithms to sequence the peptide and identify the protein source.